Peridotite

Classification Igneous
Origin Intrusive/plutonic
Composition Ultramafic
Texture Phaneritic
Common minerals Olivine
Pyroxenes

Peridotite in Hand Sample

Archean-aged peridotite from the Barberton Greenstone Belt
Peridotite from the Josephine ophiolite
Polished peridotite from the Josephine ophiolite, showing abundant enstatite
Dunite

Some call it a mantle xenolith; some call it a mantle peridotite xenolith; some call it a xenobomb. In any event, here’s a wad of olivine and pyroxene grains brought up from the mantle by the maar now known as Kilbourne Hole in New Mexico.

(Incidentally, if you’re a space exploration¬†nerd enthusiast like your friendly author is, head on over to the olivine page, scroll to the Bonus Content section at the bottom, and read up on NASA’s use of Kilbourne Hole.)

Peridotite in Thin Section

Peridotite from the Josephine ophiolite, plane polars (also an object lesson in air bubbles)
Peridotite from the Josephine ophiolite, crossed polars

Peridotite from the Josephine ophiolite, plane polars

Peridotite, Plane Polars

Peridotite in plane polarized light. Magnification: 40x Click here to watch peridotite rotate in crossed polars: https://youtu.be/-3wI5LI5CDc Click here to e…

Peridotite from the Josephine ophiolite, crossed polars

Peridotite, Crossed Polars

Peridotite in cross polarized light. Magnification: 40x Click here to watch peridotite rotate in plane polars: https://youtu.be/NQkzInMzXHM Click here to exp…